The present invention relates to an airflow straightening structure of an automotive vehicle, in which a slit and a connection portion are adjacently provided at a rear-end edge portion of a cover having a substantially-flat airflow straightening face extending in a vehicle longitudinal direction.
In general, straightening an underfloor or the like of an automotive vehicle has been achieved by using a cover for the purpose of improving the fuel economy (gas mileage). While it is preferable in order to make traveling air peel off (separate) that a rear edge portion of the cover be formed in an acute (sharp) angle shape, in a case where a fiber-based material having the high sound absorbing performance is applied to the cover, it is difficult to form the rear edge portion of the cover in the acute angle shape.
Japanese Patent Laid-Open Publication No 2007-283912 discloses a structure in which an under cover, which is a resin molding product made of polyamide resin or the like, is provided with a protrusion portion which integrally comprises a front side portion which is configured such that its front side is located at a higher level than its rear side and a rear side portion which is continuous from a lower end of the front side portion and extends obliquely rearward such that its rear side is located at a higher level than its front side, and a slit is provided at a portion of the rear side portion which is positioned just in back of the front side portion, thereby increasing the traveling-air peeling off (separation) performance.
Herein, in a case where the above-described traveling-air peeling off (separation) structure is applied to a whole part, in the vehicle width direction, of the cover, if the length of the vehicle width direction of the slit is set to be long, the strength of the cover may decrease improperly. Accordingly, it is necessary to form a connection portion (non-slit forming portion) for reinforcing. However, this connection portion (non-slit forming portion) provides the poor traveling-air peeling off (separation) performance, so there was room for improvement in this regard.